Rachel Held Evans, a best-selling author who challenged conservative Christianity and gave voice to a generation of wandering evangelicals wrestling with their faith, died on Saturday at a hospital in Nashville. She was 37.

Her husband, Daniel Evans, said in a statement on her website that the cause was extensive brain swelling. During treatment for an infection last month, Ms. Evans began experiencing brain seizures and had been placed in a medically induced coma.

“I keep hoping it’s a nightmare from which I’ll awake,” Mr. Evans said in a statement. “Rachel’s presence in this world was a gift to us all, and her work will long survive her.”

An Episcopalian, Ms. Evans left the evangelical church in 2014 because, she said, she was done trying to end the church’s culture wars and wanted to focus instead on building a new community among the church’s “refugees”: women who wanted to become ministers, gay Christians and “those who refuse to choose between their intellectual integrity and their faith.”

Ms. Evans’s spiritual journey and unique writing voice fostered a community of believers who yearned to seek God and challenge conservative Christian groups that they felt were often exclusionary.

Her congregation was online, and her Twitter feed became her church, a gathering place for thousands to question, find safety in their doubts and learn to believe in new ways.

Her work became the hub for a diaspora. She brought together once-disparate progressive, post-evangelical groups and hosted conferences to try to include nonwhite and sexual minorities, many of whom felt ostracized by the churches of their youth.

She wrote four popular books, which wrestled with evangelicalism and the patriarchy of her conservative Christian upbringing, and documented her transition to a mainline Christian identity, which moved away from biblical literalism toward affirmation of L.G.B.T. people.

Her forthcoming conference, called Evolving Faith, to be held in Denver in October, describes itself as “a gathering for wanderers, wonderers and spiritual refugees to help you discover ... You are not alone.”

Her close friends Sarah Bessey and Jeffrey Chu, with whom she organized the event, recalled how she had created space, and hope, for evangelicals questioning the institutions of their faith.

“She didn’t care at all about fame, except for how it enabled her to proclaim a more just and expansive vision of God’s love, to encourage others, and to amplify voices that are typically marginalized in the Church and in the world,” Mr. Chu wrote in an email.

Also in an email, Ms. Bessey said, “One thing about her that I have heard over and over in these days is how relentlessly she championed the voices and experiences of others, especially those whose voices were ignored or marginalized in the Church.”

Ms. Evans was known to challenge traditional — and largely male and conservative — authority structures. She would spar with evangelical men on Twitter, debating them on everything from human sexuality to politics to biblical inerrancy.

One of those men, Russell Moore, president of the Ethics and Religious Liberty Commission of the Southern Baptist Convention, said that he was her theological opposite in almost every way, but that she had always treated him with kindness and humor.

“I was on the other side of her Twitter indignation many times, but I respected her because she was never a phony,” Mr. Moore said. “Even in her dissent, she made all of us think, and helped those of us who are theological conservatives to be better because of the way she would challenge us.”

Her voice was accessible, raw and piercing, and it interrupted what was more commonly heard in evangelical circles. She drew thousands of followers.

“I will sow the seed I have received. Thank you @rachelheldevans,” wrote Alexandria Beightol, a young evangelical, on Twitter. “I’m still a Christian thanks to you. Your legacy includes the thousands of young girls who know God doesn’t hate them.”

Rachel Grace Held was born on June 8, 1981, in Alabama to Peter and Robin Held. When she was 14, the family moved from Birmingham to Dayton, Tenn., in the Bible Belt, where her father took an administrative job at Bryan College.

In 2003, she earned a bachelor’s degree in English from Bryan College, which was founded in honor of William Jennings Bryan “to teach truth from a Biblical perspective.” The college was chartered following the 1925 Scopes Trial in Dayton, during which Bryan defended a state law barring the teaching of evolution.

She married Mr. Evans, her college boyfriend, the same year she graduated. In addition to him, she is survived by their two children, a 3-year-old boy and a girl who is about to turn 1.

After moving to Chattanooga, Tenn., where she worked as an intern for The Chattanooga Times Free Press, she returned to Dayton in 2004 and joined The Herald-News. In 2007, she won an award from the Tennessee Press Association for the best personal humor column.

Ms. Evans started a blog and in 2010 published her first book, “Evolving in Monkey Town,” the title a reference to the Scopes case. It was republished in 2014 under the title “Faith Unraveled: How a Girl Who Knew All the Answers Learned to Ask Questions.”

The book traced her own evolution from religious certainty, like Bryan’s, to a faith that left room for doubt.

Among her other books was “A Year of Biblical Womanhood: How a Liberated Woman Found Herself Sitting on Her Roof, Covering Her Head, and Calling Her Husband Master,” which was on The New York Times e-book nonfiction best-seller list.

Her most recent book was “Inspired: Slaying Giants, Walking on Water, and Loving the Bible Again.”

In 2015, in a column in The Washington Post, which called her “the most polarizing woman in evangelicalism,” she urged: “Want millennials back in the pews? Stop trying to make church ‘cool.’ ”

“When I left church at age 29, full of doubt and disillusionment,” she added, “I wasn’t looking for a better-produced Christianity. I was looking for a truer Christianity, a more authentic Christianity.”

In 2016, in an essay for Vox, she described herself as a “pro-life Christian” and endorsed Hillary Clinton for president.

Her last blog post appeared online on Ash Wednesday, March 6, a day of repentance. It signals the start of Lent, which ends with the celebration of resurrection on Easter Sunday.

“Whether you are a Christian or an atheist or an agnostic or a so-called ‘none,’ ” Ms. Evans wrote, “you know this truth deep in your bones: ‘Remember that you are dust and to dust you will return.’ ”

“Death is a part of life,” she added. “My prayer for you this season is that you make time to celebrate that reality, and to grieve that reality, and that you will know you are not alone.”

A version of this article appears in print on , on Page B9 of the New York edition with the headline: Rachel Held Evans, 37; Challenged Christian Culture. Order Reprints | Today’s Paper | Subscribe